Recent cases on headline news about liver metastasis such as White House Press Secretary Tony Snow’s recent diagnosis derived from his primary colon cancer, underscores the fact that liver metastasis is a major threat to cancer survivors.
Although cancer rarely begins in the liver, it is often one of the first places where cancer comes back, through metastasis, in cancer survivors. This is primarily due to the liver serving as a primary organ with a very rich blood supply along with a unique microstructure that allows cancer cells to easily enter and hold on once arriving.
“In fact, about 80% of cancers in the liver derive from primary tumors at other sites within the body,” said Dr. Sujuan Ba, the Chief Science Officer at the National Foundation for Cancer Research (NFCR). Metastatic liver cancers mainly come from primary tumors in the colon, rectum, stomach, pancreas, ovary, breast and lung. When a liver cancer is the result of spreading from colon cancer, the prognosis is usually not optimistic: 5-year survival rates may plummet to as low as 10%.
Treatment of liver metastasis varies depending on the site of the original cancer, the extent of cancer spread to the liver and many other factors. If the metastatic cancer is restricted to one or a few discrete areas within the liver, surgical removal may provide a cure. In other cases, chemotherapy is often used and may produce a therapeutic response in 20% of liver cancer patients. In most cases however, the disease is currently not curable.
Researchers at NFCR believe that with the advancement of technology and ever-growing knowledge about this disease, major improvements in the treatment of colon and metastatic liver cancer are within reach.
NFCR is currently supporting multiple research projects that are aimed at providing hope against liver metastasis by targeting both the primary cancers and their metastasis. NFCR scientists I. Bernard Weinstein, M.D., at Columbia University, Rakesh Jain, Ph.D., at Massachusetts General Hospital, and Wei Zhang, Ph.D., at M.D. Anderson Cancer Center, are exploring alternative routes to tackling primary colorectal cancer cells more effectively. This reduces the cancer cells chances of spreading to the liver and other vital organs. Their research has led to the identification of novel molecular targets, new biomarkers and more potent therapies for the treatment of primary colorectal cancer.
It is much more difficult to treat cancer after metastasis occurs. The good news is scientists at NFCR Center for Metastasis Research may have found some clues against the stealthy spread of cancer. Led by Center Director Danny Welch, Ph.D., researchers at this NFCR Center have discovered several “metastasis suppressors” that prevent cancer cells from growing in the distant sites of the body after they arrive. Metastasis suppressors have been shown to inhibit the spread of breast, prostate, ovarian cancers and melanoma (skin cancer).
As noted by Gloria Gamat in her blog Cancer Commentary, cancer metastasis is still a mystery to scientists, but there is progree being made:
This study makes a significant contribution to the theory of cancer metastasis. Many scientists believe that cancer spread starts after the primary tumour has reached maturity. But this research challenges that and suggests that cancer cells start migrating to other sites from the start. And the same genes that drive the growth of the primary tumour also help the cells to move and settle somewhere else.
Another potential contribution this study makes is the possibility that these same genes are involved in fuelling metastasis of other cancers, or at least that similar rules are involved. That is the hope expressed by Christoph Klein, who studies metastasis at the University of Regensburg in Germany.
While this study sheds valuable light on the mystery of metastasis, there are still areas that puzzle experts. For instance, some patients are diagnosed with metastased tumours without the primary tumour every being found. And nobody knows why different cancers spread to particular tissues, such as why breast cancer travels to lung and bone in particular.